Hairballs (trichobezoar) occur in many animals, including cattle, cats, rats, rabbits, primates, and humans. (Runnells et al, Principles of Veterinary Pathology, 7th Ed., The Iowa State University Press, Ames, Iowa, 1965; Anastasia et al, 1990; Newman et al, Gastric trichobezoars-sonographic and computed tomographic appearance. Ped. Radiol., 20:526-527 1990.) Hairballs actually consist of a mixture of hair, mucous, food particles, and mineral salts. (Runnels et al, (Id.))
Hairballs result upon consumption of hair by an animal. This typically occurs as a result of dermatitis or the animal grooming itself or a companion animal. Because of the natural grooming behavior of some animals, such as rabbits and cats, hairballs are quite prevalent therein.
Not surprisingly, animals with lengthy coats are more predisposed to hairballs. However, hairballs can manifest themselves in animals having any length of hair.
Studies have shown that cats normally may spend as much as one-third of their waking hours cleaning and grooming themselves. Increased hair loss may occur as a result of disease (e.g., neuroses, excessive grooming, and dermatological related conditions) and because of normal seasonal fluctuations (molting) that may increase in the summer and decrease in the winter compared to spring or fall. (Hendricks, Protein metabolism in the adult domestic cat (Felis Catus), Ph.D. Thesis, Massey University, Palmerston North, New Zealand, 1996.) In cats, because of the structure of their tongue, a majority of this hair becomes consumed upon grooming. (Ducommun, The Cat's Body: The Versatile Tongue. Cat Fancy, pp 32-37, 1993). On average, studies have estimated that even domestic short-haired cats lose an average of 28.1 g hair/kg body weight during the course of a year, two-thirds of which is consumed and expelled in the feces. This amount is obviously significantly greater in the long-haired cats.
Any ingested hair that is not digested or that does not otherwise pass down the digestive tract may accumulate in the stomach and form an overt hairball. The most common physiological consequences thereof are diarrhea and vomiting. (Lewis et al, Small Animal Clinical Nutrition U1, Mark Morris Associates, Topeka, Kans. 1987). However, in some instances, such as in rabbits, they may form an obstruction that can be life-threatening, absent surgical intervention.
Whether hairballs are a primary problem or a secondary manifestation of another underlying problem, such as gastric hypomobility, is a matter of debate. Conventional materials and methods for treating and preventing hairballs include the administration of lubricating agents which, in theory, should facilitate the trichobezoar in passing through the gastrointestinal tract. Also, another reported means of preventing and alleviating hairballs is the use of high fiber diets which ideally function to promote the motility of the digestive system and thereby expulsion of the hairball from the rectum. Related thereto, a product recently considered by several petfood manufacturers for preventing hairballs was reported, which is based on a combination of monounsaturated and polyunsaturated fatty acids, and for which preliminary data have suggested may reduce shedding.
Another nutritive product manufactured by Heinz, All Nature's Recipe.RTM. cat treats, contains canola oil and may provide a similar lubricant effect that promotes hairball expulsion. Additionally, All Nature's Recipe.RTM. pet foods products, including treats, are formulated to minimize adverse reactions to food (food allergies or intolerances) which may manifest themselves as dermatitis conditions. These include, by way of example, single meat protein sources in the products, natural preservative, and the absence of artificial colors, flavors and dairy products which may result in less hair loss attributable to self mutilation.
Still further, several treatments are available through various pet supply channels to prevent and/or treat hairballs. Many of these treatments are based on fiber supplementation which, as discussed above, increase the rate of passage through the intestinal tract. Hill's has endorsed this concept. (Lewis et al, (Id.)). The authors similarly report that other well known remedies for constipation may be beneficial, e.g., lubricants (mineral oil, petroleum jelly), and magnesium salts. (Lewis et al (Id.))
A problem associated with most conventional hairball treatment and prevention methods is that they tend to be anti-nutritional. They are anti-nutritional because they typically function to increase the passage of materials through the digestive tract thereby reducing nutrient digestion and absorption. Thus, better and more effective remedies for treating and preventing hairballs are needed.
Pineapple juice (Anauas comosus ) has been anecdotally advocated for use in treating hairballs in rabbits. This juice is known to contain a variety of materials, including numerous proteinases. One of these proteinases is bromelain, a sulphydryl protease that can digest many proteins. However, pineapple juice contains at least four distinct cysteine proteinases, with the major stem one being stem bromelain, and the major fruit protease being fruit bromelain. Also, ananin and comasain are additional cysteine proteinases found in pineapple stem. (Rowan et al, Biochem. J., The Cysteine Proteinases of the Pineapple Plant, 266(3):869-875, 1990.)
Related thereto, some owners of cats and specially pets have reportedly used pineapple juice and also meat tenderizers, because of their wide availability allegedly to alleviate hairballs. Also, the Merck Manual recommends the use of 10 ml of fresh or frozen pineapple juice for treatment of rabbit hairballs for a three-day period. (Fraser, Merck Veterinary Manual, 7.sup.th Edition, Merck & Co., Rathway, N.J., 1991). Also, a regimen of hairball treatment involving pineapple juice administration in rabbits at a dosage of 5 ml for five days has been reported. (Harkness et al, The Biology and Medicine of rabbits and Rodents, 3.sup.rd Edition, Philadelphia, Pa., Lea and Febinger, pp 1-230 (1989). Still further, in a study involving a mature woman, a dosage of 900 ml/day reportedly reduced a bezoar to half its size in three weeks, and completely dissolved it in thirteen weeks. A dosage of 240 mg/day reportedly prevented reoccurrence. (Feffer et al, JAMA, 236:1578, (1976))
Still another reported regimen for treating hairballs involves the administration of psyllium seed (Petromalt). Some persons have indicated that the active component contained therein is psyllium seed. However, earlier literature has suggested that diastase may instead be the active agent.
Probably the best prevention of hairballs, however, is daily brushing to remove loose hair, especially during late spring and early summer when shedding is prevalent.
Thus, based on the foregoing, various remedies have been reported for treatment and prevention of hairballs. Essentially, notwithstanding what has been reported, there still exists a need for improved treatments, i.e., which are pro-nutritional and which are convenient to the pet owner.